Sunan Abu Dawud
689
Daif+3

Narrated AbuHurayrah: The Prophet (ﷺ) said: When one of you prays, he should put something in front of his face, and if he can find nothing , he should set up his staff; but if he has no staff, he should draw a line; then what passes in front of him will not harm him

DaifAl-Albani
DaifMuhammad Muhyi Al-Din Abdul Hamid